1. Technical Field
The present disclosure relates to an OLED display screen and a method of manufacturing the same and a display apparatus including the same, and particularly to a package structure for a flexible OLED display screen.
2. Description of the Related Art
OLED (organic electroluminescence) device is considered to be the most promising flat panel display device, and also is considered to be a display technology which is the most likely to produce flexible display device. However, life problem of the OLED device restricts its industrialization pace. When an OLED device works, electrons are injected from a cathode to a transport layer. In order to increase quantity of the injected carriers and to improve luminous efficiency, cathode of the OLED is made of a material having the similar work function to that of a light emitting layer, to reduce energy barrier. However, these metals having low work function, such as magnesium, aluminum, silver, are active materials which will react easily with water vapor and oxygen in the environment, so that the device fails. At the same time, Hole Transport Layer (HTL) and Electron Transport Layer (ETL) are vulnerable to be eroded by water vapor and oxygen, which leads to damage of the pixels, thereby shortening life of the device. Accordingly, packaging technology is very important in manufacture of the OLED device. Effective packaging can prevent erosion of water vapor and oxygen and avoid aging of the organic material and thus prolong life of the OLED device.
At present, reliability of packaging of the OLED mainly depends on Thin Film Encapsulation (TFE). Structure for the TFE is a multi-layer stack structure consisted of organic and inorganic layers, in which the inorganic layer achieves a barrier effect to water vapor and oxygen while the organic layer achieves planarization effect.
For a flexible OLED device having a fixed bending region, repetition of the bending actions occurs in the bending region, TFE film is easy to be damaged, and reliability of packaging of this region affects final life of the OLED device.